Community Ecology

Question 1

What are interspecific interactions?

Answer 1

Interactions between species that affect the survival and reproduction of each species involved.
Can be categorized as +,-, or 0

Question 2

What is interspecific competition? What is it categorized as? +,-,0?

Answer 2

(-/-) interaction, occurs when species compete for a limited resource

Question 3

What is the competitive exclusion principle?

Answer 3

That competition in an unstable stale - over time, one species will out compete the other.

Question 4

What is resource partitioning?

Answer 4

Organisms specifying in their ecological niche to get their food. Each organism has their own niche to partition up the resources.
It comes up after competition has ended.
Can partition based on: resources, location, and timing

Question 5

What is character displacement? What is it driven by?

Answer 5

Character displacement is when characteristics are more divergent in sympatric populations (pops living together) than in allopatric populations (pops living apart) of the same species.
- Due to competition or lack of competition

Question 6

What is predation? What kind of impact does it have?

Answer 6

(+/- interaction) - an interaction in which one species (predator) kills and eats the other (prey)

Question 7

What is herbivory? What kind of impact does it have?

Answer 7

(+/- interaction) - an interaction where one species (usually animal) eats part or all of another species (usually plant or plant-like)

Question 8

What are 3 (of 6) anti-predator defenses?

Answer 8

1. Mechanical defense - ex. spikes on porcupine
2. Chemical defense - ex. skunk sprays chemical
3. Aposematic (warning) coloration - ex. poison dart frog

Question 9

What are the other 3 (of 6) anti-predator defenses?

Answer 9

4. Cryptic coloration (camouflage) - ex. chameleon
5. Batesian mimicry (a harmless species mimics a harmful one) - ex. Moth larvae and snake head
6. Mullerian mimicry (two unpalatable species mimic each other, converge on same warning) - ex. cuckoo bee and wasp

Question 10

What are anti-herbivore defenses?

Answer 10

Plants teaming up with other organisms to protect them, produce chemicals, or have physical defenses

Question 11

Which of the following is an example of Batesian
mimicry?
A) a butterfly that resembles a leaf
B) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish
C) a fawn with fur coloring that camouflages it in
the forest environment
D) a nonvenomous snake that looks like a venomous snake

Answer 11

D

Question 12

Which of the following is an example of Müllerian mimicry?
A) a chameleon that changes its color to look like a dead leaf
B) a day-flying hawkmoth that looks like a wasp
C) two species of unpalatable butterfly that have the same color pattern
D) two species of rattlesnakes that both rattle their tail

Answer 12

C

Question 13

What are the three types of symbioses and what are their interaction types?

Answer 13

Parasitism - (+/-) Parasite lives off of host
Mutualism - (+/+) Helping one another out
Commensalism - (+/0) One benefits, other not bothered

Question 14

Approximately what percent of all species on Earth are
parasites?
A) 1%
B) 5%
C) 35%
D) 50%

Answer 14

C

Question 15

Species diversity importance

Answer 15

Species richness is more important than species abundance. You don’t want a forest with all the same types of tree!

Question 16

What is a dominant species?

Answer 16

Species that are most abundant or have the highest biomass.

Question 17

What is a keystone species?

Answer 17

Species that have large effects on an ecosystem because of their ecological niches. (Ex. Beaver!) Many other organisms are dependent upon that species.

Question 18

What are the parts of a food chain?

Answer 18

Bottom: Primary producers (mostly plants)
Primary consumers (ex. insect)
Secondary consumers (ex. mouse)
Tertiary consumers (ex. snake)
Quaternary consumers (ex. hawk)

Question 19

What is a better model than a food chain?

Answer 19

A food web!
In reality, each species feeds on multiple other species, and is being eaten by multiple other speices.

Question 20

What do the feeding arrows represent? Who is eating who?

Answer 20

The arrows point to who is doing the eating!
Ex. arrow from squids to elephant seals. Squids are eaten by elephant seals.

Question 21

How can you determine how important a species is in a food web?

Answer 21

The species that has the most connections is the most important, because that species impacts the most amount of other species!

Question 22

Bottom-up control

Answer 22

Species controlling the population sizes of those on higher tropic levels. Lower levels affect higher levels.
Ex. Rabbit population controls the lynx population from the bottom up.

Question 23

Top-down control

Answer 23

Species controlling the population sizes of those on lower tropic levels. Higher levels affect lower levels.
Ex. The lynx population controls the rabbit population from the top down.

Question 24

Energetic hypothesis

Answer 24

The lower levels of the food chain have more individuals on that lower level. As you exchange energy/matter up the food chain, you cannot transfer all of it. Only about 10% of energy is transferred between trophic levels.
Each trophic level can only support 10% of the trophic level below it
10,000kg plant biomass can support 1,000kg herbivore biomess

Question 25

Biomagnification (life zoomed in)

Answer 25

Toxins accumulate in higher trophic levels. Each consumer eats more of the level under it, and thus the toxins accumulate as you go up the food chain.

Question 26

Are communities in equilibrium?

Answer 26

Evidence suggests a ‘non-equilibrium’ model, communities are dynamic by their very nature, because populations make up communities and populations are always changing.

Question 27

Coevolution

Answer 27

Interacting species cause evolutionary changes in one another.

Question 28

Ecological succession

Answer 28

Community structure changes following disturbance. The community recovers differently than it may have looked before.
Ex. Fire, drought, flooding, glaciers
An intermediate amount of disturbance can be very beneficial to a community! Too low or too high disturbance can cause a low amount of species diversity.

Question 29

What is the biggest disturbance to community structure?

Answer 29

Humans!
Human disturbance almost always reduces species diversity

Question 30

What is urban ecology?

Answer 30

Field that looks at how species and what species are able to survive in human procreated land.